The IPCC model simulation archive
In the lead up to the 4th Assessment Report, all the main climate modelling groups (17 of them at last count) made a series of coordinated simulations for the 20th Century and various scenarios for the future. All of this output is publicly available in the PCMDI IPCC AR4 archive (now officially called the CMIP3 archive, in recognition of the two previous, though less comprehensive, collections). We've mentioned this archive before in passing, but we've never really discussed what it is, how it came to be, how it is being used and how it is (or should be) radically transforming the comparisons of model output and observational data.
First off, it's important to note that this effort was not organised by IPCC itself. Instead, it was coordinated by the Working Group on Coupled Modelling (WGCM), an unpaid committee that is part of an alphabet soup of committees, nominally run by the WMO, that try to coordinate all aspects of climate-related research. In the lead up to AR4, WGCM took up the task of deciding what the key experiments would be, what would be requested from the modelling groups and how the data archive would be organised. This was highly non-trivial, and adjustments to the data requirements were still being made right up until the last minute. While this may seem arcane, or even boring, the point I'd like to leave is that just 'making data available' is the least of the problems in making data useful. There was a good summary of the process in Bulletin of the American Meteorological Society last month.
Previous efforts to coordinate model simulations had come up against two main barriers: getting the modelling groups to participate and making sure enough data was saved that useful work could be done.
Modelling groups tend to work in cycles. That is, there will be a period of a few years of development of a new model then a year or two of analysis and use of that model, until there is enough momentum and new ideas to upgrade the model and starting a new round of development. These cycles can be driven by purchasing policies for new computers, staff turnover, general enthusiasm, developmental delays etc. and until recently were unique to each modelling group. When new initiatives are announced (and they come roughly once every six months), the decision of the modelling group to participate depends on where they are in their cycle. If they are in the middle of the development phase, they will likely not want to use their last model (because the new one will almost certainly be better), but they might not be able to use the new one either because it just isn't ready. These phasing issues definitely impacted earlier attempts to produce model output archives.
What was different this time round is that the IPCC timetable has, after almost 20 years, managed to synchronise development cycles such that, with only a couple of notable exceptions, most groups were ready with their new models early in 2004 - which is when these simulations needed to start if the analysis was going to be available for the AR4 report being written in 2005/6. (It's interesting to compare this with nonlinear phase synchronisation in, for instance, fireflies).
The other big change this time around was the amount of data requested. The diagnostics in previous archives had been relatively sparse - the main atmospheric variables (temperature, precipitation, winds etc.) but not huge amounts extra, and generally only at monthly resolution. This had limited the usefulness of the previous archives because if something interesting was seen, it was almost impossible to diagnose why it had happened without having access to more information. This time, the diagnostic requests for the atmospheric, ocean, land and ice were much more extensive and a significant amount of high-frequency data was asked for as well (i.e. 6 hourly fields). For the first time, this meant that outsiders could really look at the 'weather' regimes of the climate models.
The work involved in these experiments was significant and unfunded. At GISS, the simulations took about a year to do. That includes a few partial do-overs to fix small problems (like an inadvertent mis-specification of the ozone depletion trend), the processing of the data, the transfer to PCMDI and the ongoing checking to make sure that the data was what it was supposed to be. The amount of data was so large - about a dozen different experiments, a few ensemble members for most experiments, large amounts of high-frequency data - that transferring it to PCMDI over the internet would have taken years. Thus, all the data was shipped on terabyte hard drives.
Once the data was available from all the modelling groups (all in consistent netcdf files with standardised names and formatting), a few groups were given some seed money from NSF/NOAA/NASA to get cracking on various important comparisons. However, the number of people who have registered to use the data (more than 1000) far exceeded the number of people who were actually being paid to look at it. Although some of the people who were looking at the data were from the modelling groups, the vast majority were from the wider academic community and for many it was the first time that they'd had direct access to raw GCM output.
With that influx of new talent, many innovative diagnostics were examined. Many, indeed, that hadn't been looked at by the modelling groups themselves, even internally. It is possibly under-appreciated that the number of possible model-data comparisons far exceeds the capacity of any one modelling center to examine them.
The advantages of the database is the ability to address a number of different kinds of uncertainty, not everything of course, but certainly more than was available before. Specifically, the uncertainty in distinguishing forced and unforced variability and the uncertainty due to model imperfections.
When comparing climate models to reality the first problem to confront is the 'weather', defined loosely as the unforced variability (that exists on multiple timescales). Any particular realisation of a climate model simulation, say of the 20th Century, will have a different sequence of weather - that is, the weather pattern on Jan 31, 1967 in one realisation will be uncorrelated to the weather pattern on Jan 31, 1967 in another realisation, even though each run has the same climate forcing (increases in greenhouse gases, volcanoes etc.). There is no expectation that the weather in any one model will be correlated to that in the real world either. So any comparison of climate models and data needs to estimate the amount of change that is due to the weather and the amount related to the forcing. In the real world, that is difficult because there is certainly a degree of unforced variability even at decadal scales (and possibly longer). However, in the model archive it is relatively easy to distinguish.
The standard trick is to look at the ensemble of model runs. If each run has different, uncorrelated weather, then averaging over the different simulations (the ensemble mean) gives an estimate of the underlying forced change. Normally this is done for one single model and for metrics like the global mean temperature, only a few ensemble members are needed to reduce the noise. For other metrics - like regional diagnostics - more ensemble members are required. There is another standard way to reduce weather noise, and that is to average over time, or over specific events. If you are interested in the impact of volcanic eruptions, it is basically equivalent to run the same eruption 20 times with different starting points, or collect together the response of 20 different eruptions. The same can be done with the response to El Niño for instance.
With the new archive though, people have tried something new - averaging the results of all the different models. This is termed a meta-ensemble, and at first thought it doesn't seem very sensible. Unlike the weather noise, the difference between models is not drawn from a nicely behaved distribution, the models are not independent in any solidly statistical sense, and no-one really thinks they are all equally valid. Thus many of the pre-requisites for making this mathematically sound are missing, or at best, unquantified. Expectations from a meta-ensemble are therefore low. But, and this is a curious thing, it turns out that the meta-ensemble of all the IPCC simulations actually outperforms any single model when compared to the real world. That implies that at least some part of the model differences is in fact random and can be cancelled out. Of course, many systematic problems remain even in a meta-ensemble.
There are lots of ongoing attempts to refine this. What happens if you try and exclude some models that don't pass an initial screening? Can you weight the models in an optimum way to improve forecasts? Unfortunately, there doesn't seem to be any universal way to do this despite a few successful attempts. More research on this question is definitely needed.
Note however that the ensemble or meta-ensemble only gives a measure of the central tendency or forced component. They do not help answer the question of whether the models are consistent with any observed change. For that, one needs to look at the spread of the model simulations, noting that each simulation is a potential realisation of the underlying assumptions in the models. Do not - for instance, confuse the uncertainty in the estimate of the ensemble mean with the spread!
Particularly important simulations for model-data comparisons are the forced coupled-model runs for the 20th Century, and 'AMIP'-style runs for the late 20th Century. 'AMIP' runs are atmospheric model runs that impose the observed sea surface temperature conditions instead of calculating them with an ocean model, optionally using other forcings as well and are particularly useful if it matters that you get the timing and amplitude of El Niño correct in a comparison. No more need the question be asked 'what do the models say?' - you can ask them directly.
The usefulness of any comparison is whether it really provides a constraint on the models and there are plenty of good examples of this. What is ideal are diagnostics that are robust in the models, not too affected by weather, and can be estimated in the real world e.g Ben Santer's paper on tropospheric trends, the discussion we had on global dimming trends, and the AR4 report is full of more examples. What isn't useful are short period and/or limited area diagnostics for which the ensemble spread is enormous.
CMIP3 2.0?
In such a large endeavor, it's inevitable that not everything is done to everyone's satisfaction and that in hindsight some opportunities were missed. The following items should therefore be read as suggestions for next time around, and not as criticisms of the organisation this time.
Initially the model output was only accessible to people who had registered and had a specific proposal to study the data. While this makes some sense in discouraging needless duplication of effort, it isn't necessary and discourages the kind of casual browsing that is useful for getting a feel for the output or spotting something unexpected. However, the archive will soon be available with no restrictions and hopefully that setup can be maintained for other archives in future.
Another issue with access is the sheer amount amount of data and the relative slowness of downloading data over the internet. Here some lessons could be taken from more popular high-bandwidth applications. Reducing time-to-download for videos or music has relied on distributed access to the data. Applications like BitTorrent manage download speeds that are hugely faster than direct downloads because you end up getting data from dozens of locations at the same time, from people who'd downloaded the same thing as you. Therefore the more popular an item, the quicker it is to download. There is much that could be learned from this data model.
The other way to reduce download times is to make sure that you only download what is wanted. If you only want a time series of global mean temperatures, you shouldn't need to download the two-dimensional field and create your own averages. Thus for many purposes, automatic global, zonal-mean or vertical averaging would have saved an enormous amount of time.
Finally, the essence of the Web 2.0 movement is interactivity - consumers can also be producers. In the current CMIP3 setup, the modelling groups are the producers but the return flow of information is rather limited. People who analyse the data have published many interesting papers (over 380 and counting) but their analyses have not been 'mainstreamed' into model development efforts. For instance, there is a great paper by Lin et al on tropical intra-seasonal variability (such as the Madden-Julian Oscillation) in the models. Their analysis was quite complex and would be a useful addition to the suite of diagnostics regularly tested in model development, but it is impractical to expect Dr. Lin to just redo his analysis every time the models change. A better model would be for the archive to host the analysis scripts as well so that they could be accessed as easily as the data. There are of course issues of citation with such an idea, but it needn't be insuperable. In a similar way, how many times did different people calculate the NAO or Niño 3.4 indices in the models? Having some organised user-generated content could have saved a lot of time there.
Maybe some of these ideas (and any others readers might care to suggest), could even be tried out relatively soon…
Conclusion
The diagnoses of the archive done so far are really only the tip of the iceberg compared to what could be done and it is very likely that the archive will be providing an invaluable resource for researchers for years. It is beyond question that the organisers deserve a great deal of gratitude from the community for having spearheaded this.
4 février 2008 at 12:40 PM
Ok Gavin, all well and good, and I am sure that this “new archive” will continue to confirm your previous “findings” of Global Warming based on human activities. I put it to you that all of your models may in fact be based on a major flaw. The assumption that the earth is round and not flat. Why don’t you do a complete recalculation based on the flat earth thesis and then we will see. Of course as a sceptic with lots of opinions and no scientific training I cannot be expected to do any actual real work on this matter but I do expect you to turn your life’s work upside down to answer my argument (that is how the game played isn’t it?).
Besides even if the world warms and the Arctic, Antarctic and Greenland ice caps all melt it will not be an issue. Like I just told you the earth is flat and the excess water will just fall of the edge. What stops the existing water from flowing off, I hear you ask, well you are the scientist why don’t you work it out?
Actually I am continually amazed at the amount of well reasoned detail presented on this site and your seemingly endless patience in explaining and re-explaining the basics of the science.
Thank you
Gerald
4 février 2008 at 1:00 PM
Very clear, except:
What is WMO?
[Response: World Meteorological Organization. -rasmus]
4 février 2008 at 2:02 PM
Thanks, Gavin, for this interesting insight. I’m somewhat intrigued by the performance of the ensemble averages. Has anyone done any sort of jacknifing or bootstrapping analysis that looks at performance eliminating one or more models from the average? Since you don’t really know how things are distributed, this might be the only way to explore the variability.
4 février 2008 at 2:10 PM
Archives are very good, yes. However, as a science communicator / technical illustrator, I find the “Terms of Use” in these model comparison projects to be toxic:
I can’t so much as make a Wikipedia plot without violating those terms, since those plots aren’t part of any “research project” intended for academic publication. And I certainly couldn’t use the data to make plots for books, magazines, or other commercial publications.
Computer climate modeling is (usually) funded by public funds, so it seems strange to create any strong restrictions on the further use of that data.
You mention:
Does that include relaxing the non-commercial, academic paper oriented requirements?
[Response: Non-commercial will probably stay. That is because many of the national modelling groups (not in the US though) have mandates to make money as well as do research and would not contribute to these archives if they felt their paid work would be undermined. I imagine that they are worried about someone else downscaling their projections and selling it as regional climate forecasts. However, I see no reason for other restrictions. Open access should definitely allow, nay encourage, more casual use of the data. I will query the organisers and see what is planned. - gavin]
4 février 2008 at 2:15 PM
I’d like to thank the climate science community in general for the high degree of free access to data. I’m a data analysis junkie, after all, and I could spend several lifetimes just analyzing the data I’ve already saved on my computer.
It would be lifetimes well spent.
4 février 2008 at 4:09 PM
Gavin,
I think it’s a bit of an understatement to say that not everything at the archive is done to everyone’s satisfaction.
In fact, there’s some mysterious vetting process that comes into play when you register at the archive. If you pass, you’re granted access. If not, you’re invited to apply again. And again. And again.
An example: I applied for access to the archive last year. My goal was to add this valuable data to an archive that I maintain that makes it relatively easy (I hope) to download and/or visualize geophysical data. I was repeatedly denied access. It took four months and the threat of a formal FOIA request before I was allowed any access at all. And I still only have access to the US model data.
Any idea when this archive will truly be open?
[Response: The problem was that some groups were not ok with third parties hosting the data. This was not a problem for any of the US groups though. The fully open access was proposed a couple of months back and no-one (AFAIK) seemed to mind. Thus I would anticipate that it is imminent. If someone who has actual knowledge wants to let me know, they can email or leave or comment here. - gavin]
4 février 2008 at 4:19 PM
Since you ask for suggestion(s):
Wouldn’t it be interesting to run a large ensemble of coupled runs and cherry-pick the ones whose SST’s match observations? You could compare the range of weather patterns with that of both the “un-picked-over” ensemble and the ‘AMIP’ runs.
4 février 2008 at 7:19 PM
David B. Benson @ 2: WMO = World Meteorological Organization, http://www.wmo.ch/
4 février 2008 at 7:41 PM
Re. 1 “What is WMO”:
World Meteorological Organization
http://www.wmo.ch/pages/about/index_en.html
“The World Meteorological Organization (WMO) is a specialized agency of the United Nations. It is the UN system’s authoritative voice on the state and behaviour of the Earth’s atmosphere, its interaction with the oceans, the climate it produces and the resulting distribution of water resources.”
4 février 2008 at 8:18 PM
“The other way to reduce download speeds is to make sure that you only download what is wanted. ”
I think you meant “the other way to increase download speeds…”
minor point.
[Response: true. I’ve changed it to ‘download time’. - gavin]
4 février 2008 at 8:20 PM
re # 1
My Google must be dumber than yours. I get “World Meteorological Organization (WMO) Homepage - Organisation …World Meteorological Organization - Official United Nations’ authoritative voice on weather” over and over. I can not find enough differnt possible choices to turn it into a good question.
4 février 2008 at 9:00 PM
Have any statisticians experienced in meta-analysis looked at these archives? Meta-analysis , especially using Bayesian approaches has been used a lot especially in medical fields.
The differences in the plausibility of models to me seems to invite a Bayesian approach. I would suggest seeking out some statisticians with the appropriate expertise.
4 février 2008 at 9:10 PM
#1
world meteorological organizaion
4 février 2008 at 9:50 PM
Re: #1 (gerald)
I nominate you for “best comment ever.”
4 février 2008 at 10:16 PM
This post/thread offers some interesting and helpful insights. A couple of questions: 1) I didn’t fully comprehend “unfunded”. Does this mean that no funds were from IPCC, WGCM, or WMO or other UN-related body and that all funding came from the enterprises employing the scientists and buying the computers? Surely the guys and gals did not work for no pay…??? Question is: who paid the bills?
2) I too am bothered by the raw averaging process for meta-ensemble. But is ther any other process that could have been clearly better? Also, you imply that everyone ‘lucked out’ when the meta averaging came out better that any one model (I assume by comparing historical information…???). But none-the-less shouldn’t there still be a pile of concern/nervousness/interest? There seems to be at least a small thread that says you have validated the models with a process a little like playing the slots.
4 février 2008 at 10:49 PM
Lloyd, search: +climatologist +Bayesian
See also: http://www.cell2soul.org/issues/article.php?issue_dir=v2/i2&article_num=a18
The Patient from Hell: How I Worked with My Doctors to Get the Best of Modern Medicine and How You Can Too by Stephen H. Schneider, with Janica Lane
De Capo Lifelong Books (2005); 300 pages;
ISBN: 0738210250
http://www.patientfromhell.org
“… applied subjective probability analysis (Bayesian updating) based on knowledge, experience, and intuition when conclusive hard data is lacking; examined historical data to calculate risk, from mild to catastrophic (risk = probability + consequence); and repeatedly determined whether to push for a Type I risk, where one spends the money and acts to prevent a bad outcome despite lack of surety of the symptom, or whether to accept a Type II risk, where one saves the money and doesn’t act, accepting that the consequences may be disastrous after all….”
4 février 2008 at 11:43 PM
Re: Gavin’s response #4,
If there have to be restrictions to appease some national modeling groups, then those restrictions really should be displayed at the dataset level rather than having a blanket policy covering the entire portal. Appeals to the most restrictive preferences are inherently counter-productive. Not to mention that even within modeling groups, some data is treated more freely than others (e.g. the Hadley Centre policy on summary datasets).
[Response: Agreed. - gavin]
5 février 2008 at 2:01 AM
gavin:
Isn’t this just a result of — and an indication — that all models contain flaws, but they are mostly different flaws for each different model? Then, when you construct a meta-ensemble, you just ‘dilute’ each flaw with all the non-so-flawed other models. No statistics/stochastics/randomness involved.
Do I miss something?
[Response: Yes. But that is a statistical effect. The flaws (in some measure) must be statistically independent. - gavin]
5 février 2008 at 5:56 AM
Many thanks for this, Gavin, very useful.
I would add to some of the comments above about the importance of considering other statistical approaches and modes of presentation. In my own work, I use metamodels and bootstrapping techniques, and am moving towards adopting some of the Bayesian methods noted above e.g. based on Kennedy and O’Hagan, 2001 (although I don’t myself think they are always the best approach or the most suitable - depends a lot upon the aim of the intended analysis and type of research question).
One thing I am also working on is the presentation of altenative predicted futures and associated risk, using a modified kind of contingency table. By this method, one takes into account the equifinality inherent in most, if not all, of the types of model commonly used in the geosciences; I would imagine that climate models suffer similar problems, so it would be useful at some point (when I can make some time, dammit!) to have a go at these, too. Hence an archive like this is of great value.
More of the same!
5 février 2008 at 7:51 AM
Rod B. asks about the issue of underfunding:
“Surely the guys and gals did not work for no pay…??? Question is: who paid the bills?”
Actually, that is probably precisely what it means–a lot of unpaid overtime. This is quite common in the sciences. I typically work 60 hours in an average week. During crunch times I work 80. I am not atypical. We rationalize this often by saying our work is our hobby as well as our day job. The fact of the matter is that grants rarely cover all the work that needs to be done to publish papers. The government learned long ago that most scientists are more motivated by a challenging problem than by a paycheck.
He then asks about the averaging process for the ensemble and whether there might be a better way of doing the average.
One possibility might be to use weights based on how the models according to various information criteria (e.g. AIC, BIC, TIC, etc.). This would allow models of different complexities to be compared and ensure that overfit models were downweighted approproately. Note that the AIC would (of course) have to be based on the information used to calibrate the model, not how well the model predicted the phenomenon under study. Actually, model averaging has been found to outperform the results of any single model, especially when models are appropriately weighted. What this may be telling you is that no particular model is vastly superior to any other. Also note that such a process is compatible with Lloyd’s suggestion of a Bayesian meta-analysis.
5 février 2008 at 8:05 AM
I don’t beleive IPCC - it estimates that aviation is responsible for around 3.5% of anthropogenic climate change?!
http://www.climateactionprogramme.org/news/article/reducing_airline_emissions_can_it_be_done/
5 février 2008 at 8:41 AM
Three things:
1) Next time round we are planning on a distributed archive, which will allow download of subsets (in space and time). Planning for this is actively underway. It’s not obvious that download speeds will be actively enhanced by the distribution though, because the data volumes this time around are likely to minimise the number of copies which can exist.
2) Regrettably it is likely that much data in the archive will have more restricted access conditions than the American participants can allow. Gavin’s explanations is correct.
3) Funding: In general the UN and IPCC can’t spend money, they ask the nation states to do things, which then get funded “locally”. The AR4 archive that Gavin is describing was funded by internal US funds. As I understand it, it was unfunded in the sense that the archive hosts moved money from another task to support the archive. For the next assessment report we hope that a number of other nations will be contributing effort and sharing the load …
5 février 2008 at 9:06 AM
Speaking of model meta-analysis - is there a comparison available of the slow response times/lags in the system, among the different models? I was curious, for example, how much further different metrics would change (and how quickly) if magically, all greenhouse gas emissions stopped completely tomorrow. Or, alternatively, if the CO2 concentration instantaneously jumped from 280 to 380 ppmv, how long it would take for metrics to approach a new equilibrium.
[Response: The simulation that everyone did was to fix concentrations at 2000 levels (’committment runs’). It takes a few decades to get 80% or so of the way to equilibrium, and much longer for the remaining 20%. Sea level rise (due to thermal expansion) continues for centuries. There was a paper by Meehl et al (2005) that discussed this. - gavin]
5 février 2008 at 11:02 AM
Gavin,
In your response to #23 you talk of the decades and more it takes to reach equilibrium once CO2 concentrations stabilize. I presume this passage of time is related to the “heat in the pipeline” and the lag in heating the oceans. While this is logical (to me) and presumably based on sound science, I don’t see a lag in temperature behavior as depicted by the GISS land and ocean surface temperature record here:
http://data.giss.nasa.gov/gistemp/graphs/
The ocean surface temperatures go up and down (at a smaller magnitude) at the same time as the land surface temperatures. I see no evidence of a lag going back to the beginning of the record in 1880. Why is this?
[Response: In Fig A4 the ocean temperatures are clearly damped compared to Land. There are multiple timescales here though - some are short (seasonal and interannual) which make many short term anomalies line up, but the long time scales come into the problem for the long term trend and they are the ones that come into play for the “in the pipeline” effect. - gavin]
5 février 2008 at 11:06 AM
Peter says: “I don’t beleive IPCC - it estimates that aviation is responsible for around 3.5% of anthropogenic climate change?!”
And since your “belief” is not based on any evidence or even any facts that you have cited, it is relevant to the discussion exactly…how?
5 février 2008 at 11:16 AM
An excellent initiative! Please keep pressing for maximum access, Gavin.
5 février 2008 at 11:29 AM
Is there any way to establish a ranking of the 17 modelling groups, by their success in predicting changes in climate - if that is what they are working on? If their goal is something different, how would success in that endeavor be measured? Thank you.
[Response: The best you can do so far is assess the skill of the climatology (no trends) - Reichler and Kim have done some work on that (see here). Success in projections will need some more time. - gavin]
5 février 2008 at 11:52 AM
Ray, I like your notion of wanting the “exact” information on relevant issues. Speaking towards this, please tell me exactly how the IPCC gets to 2.5-3 degrees C temperature increase from doubled CO2.
I thank you in advance for your assistance.
[Response: We’ve gone over why the ‘best guess’ climate sensitivity is 3 deg C a dozen times. It’s not a secret. - gavin]
5 février 2008 at 12:11 PM
A few more comments:
1) Funding: I’m not sure how much finding (if any) the archive hosts received for
the AR4 simulations. However, they apparently have received about
$13.5 million (over five years) for the next round of
simulations. I don’t know if any of this will go to the modeling
centers to defray the costs of preparing data for archival.
2) Last time I checked, none of the AR4 data (including US data) were
available for public download via ftp or http. Even though the USA data
*are* freely available via OPeNDAP, there is no mention of this anywhere at
the archive Web site. There’s no reason why there should be any
restrictions on access to the US data.
3) One of the WGCM members told me a few months ago that rumor had it
(he wasn’t actually at the meeting) that at least one
modeling group (Hadley) was opposed to opening up the AR4
archive.
4) The rules for who is or is not allowed to access the archive need to be
clearer. For instance, who decides whether an applicant is
permitted to use the archive? What are the ground rules for making
this decision?
5) It’s really unfortunate that the next archive will be as restricted as
the present one. I think the modeling and archive centers have a lot
to learn from the open source software community.
[Response: I can’t speak for other modelling groups, but much of the GISS data is available on our own servers. GISS received no additional money over our standard model development grants to do simulations for AR4, and most groups were in the same boat. Discussion of how the next archive will be set up is ongoing, and you should be vocal in sharing your concerns. None of these things appear insuperable. - gavin]
5 février 2008 at 12:12 PM
The aviation figure does seem high to me — has anyone checked whether it makes sense? What are the respective magnitudes involved? I don’t think you could get that much from the well-mixed greenhouse gases alone produced by jet engines; is there an effect from creating high-altitude cirrus clouds?
5 février 2008 at 12:54 PM
Thanks to all who responded regarding WMO. I ought to have guessed the answer. Anyway, the link was of interest.
5 février 2008 at 1:23 PM
Gaelan, I’m not sure I understand your question. I presume you can read English. You are as capable of going to the summaries as I am. Or did you just want to say something clever and this was the best you could do on short notice?
5 février 2008 at 1:33 PM
Re #21
A Boeing 747-400ER starts with 63,500 US gal of fuel for a long flight, which is about 50% of the take-off weight. The new super jumbo A380A has a capacity for 83,500 US gal of fuel. The fuel burn rate of a Boeing 737-400 is about 3,000 liters per hour. If you add up all the emmisions from all classes of aviation (i.e., private, commercial, government and military), I wouldn’t be suprised that total is much higher.
Hydrocarbons fuels will always be used by boats, planes, freight trains and trucks, construction, mining
forestry and agricultural machinery, all military vehicles and mobile weaponary (e.g., tanks), most all cars and light trucks, diesel-electric generating systems which are used extensively thru out the world (e.g., in small countries and at gold and diamond mines), etc because these fuels have high energy densities. They are readily prepared from crude oil by fractional distillation and blending, low energy processes that do not involve the breaking and making of chemical bonds. These fuels are highly portable and can be stored indefinetly in sealed containers or tanks under an inert nitrogen atmosphere. Hydrocabons fuels are chemically inert (except to oxygen, halogens and certain other highly reactive chemicals) and do not corrode metals or attack rubber and other materials(e.g, gaskets) used for construction of engines. Since gasoline has a flash point of -40 deg C, it can be used in very cold climates.
Some other heavy hitters that will always use megagobs of fossil fuels are lime and cement kilns, metal smelters (especially steel mills), founderies making engine blocks, pipe, tools, big nuts and bolts, rail car wheels, etc, all factories that manufacture ceramics materials and products (e.g., bricks, blocks, tiles, pottery, dishes, glass sheets and bottles, etc), all food preparation (e.g, large bakeries) and processing (e.g., sterilization). Fossil fuels will always be used for residential space and water heating especially in cold climates.
The chemical process industries require petroleum feedstocks and use lots of energy for the manufacure of an amazing array of materials such as carpet and cloth fibers, paint, plastics, exotic material like silicones and Teflon, and so forth.
I could go on on listing all the human activities that will always use fossil fuels because there never will be any suitable and economical subsitutes with requisite physical and chemical properties.
The bottom line is this: There never ever will be a reduction in the consumption of or the phase out fossil fuels and consequently no reduction in the emission of greenhouse gases.
5 février 2008 at 2:02 PM
Re Harold Pierce @ 21: “Hydrocarbons fuels will always be used by boats, planes, freight trains and trucks, construction, mining…”
Mainline electrified freight railroad milage was once quite extensive in North America and there is no reason why it could not be again. Of course, there would be no net gain unless the electrical power is produced without burning fossil carbon. Ocean shipping was once entirely wind-powered and there is great potential for at least reducing the amount of fossil carbon fuel use by augmenting with sail power.
“Some other heavy hitters that will always use megagobs of fossil fuels are lime and cement kilns, metal smelters (especially steel mills), founderies making engine blocks, pipe, tools, big nuts and bolts, rail car wheels, etc…”
Perhaps you’ve not heard of electric arc furnaces, which have extensively displaced open hearth furnaces in steel making and smelting, with the electricity sometimes even produced by carbon-free hyrdoelectric plants.
Never say never, it’ll trip you up every time.
5 février 2008 at 2:09 PM
Ray (20), Interesting; thanks.
5 février 2008 at 2:20 PM
re #33 (Harold Pierce Jr) “The bottom line is this: There never ever will be a reduction in the consumption of or the phase out fossil fuels and consequently no reduction in the emission of greenhouse gases.”
Pretty big claim, there, Harold, don’t you think? What assumptions are you *really* making? Over what timescales? And what uncertainties are there around your assumptions, I wonder?
re # 20 (Ray Ladbury) “This would allow models of different complexities to be compared and ensure that overfit models were downweighted approproately.”
Ray, would you just clarify for me what you mean here by ‘overfit’? I may be confusing this with ‘overfitted’ i.e. the possibility that the underlying model functionality is more complex than necessary to explain the variance and trends in the system. (It’s a nice problem to have to untangle). I’m also interested in the weighting procedure, and to what extent this applies to functional parameters (process rate coefficients, exponents, thresholds, that sort of thing) as well as models as a whole. Any core refs here, for example?
5 février 2008 at 2:21 PM
RE #33 [Harold Pierce Jr.] “The bottom line is this: There never ever will be a reduction in the consumption of or the phase out fossil fuels and consequently no reduction in the emission of greenhouse gases.”
Well, you live and learn. I’ve been thinking the Earth (and therefore the supply of fossil fuels) was finite!
5 février 2008 at 2:23 PM
No Ray, I intend nothing clever. Indeed, the question is pretty straightforward and requires no inference as to intention. Just an answer as to the exposition of the supposed temperature increase for the doubling of atmospheric CO2. If you don’t have the answer just say so.—I can not understand that you do not understand.
Dr. Schmidt has been kind enough to advise that this is a “best guess”, which is ok if we are gambling with our own money. But when the gamble is with the collective pocket books of the entire planet, I posit we need better than a “guess”.—A “guess” by the way that is not clearly stated anywhere in the IPCC literature of possible doomsday scenarios that, according to the IPCC, have I very high probability of occuring—–that does not sound like a “guess” to me.
So, Ray, when you ask for others their “exact” information, why is it so hard for you to reference yours?
5 février 2008 at 2:50 PM
Harold Pierce #33 is right. The six or seven billion people in the world burn stuff every day of their lives. Do we really think we can regulate them all to change their way of life? If the production of CO2 is going to change the climate, then we ought to prepare for it. It makes more sense to get off the tracks then it does trying to stop the train.
5 février 2008 at 2:54 PM
Harold Pierce Jr (33) — Au contriare, visit
http://biopact.com/
to discover the biofuel alternatives being developed for all the uses you mention, except aviation, where 50% biofuel appears to be the goal.
5 février 2008 at 4:15 PM
Harold Pierce writes:
[[I could go on on listing all the human activities that will always use fossil fuels because there never will be any suitable and economical subsitutes with requisite physical and chemical properties.
The bottom line is this: There never ever will be a reduction in the consumption of or the phase out fossil fuels and consequently no reduction in the emission of greenhouse gases.]]
You do realize the supply of the stuff is FINITE, right?
5 février 2008 at 4:17 PM
Gaelan Clark writes:
[[Dr. Schmidt has been kind enough to advise that this is a “best guess”, which is ok if we are gambling with our own money. But when the gamble is with the collective pocket books of the entire planet, I posit we need better than a “guess”.—A “guess” by the way that is not clearly stated anywhere in the IPCC literature of possible doomsday scenarios that, according to the IPCC, have I very high probability of occuring—–that does not sound like a “guess” to me.]]
Here are 61 estimates:
http://members.aol.com/bpl1960/ClimateSensitivity.html
5 février 2008 at 4:18 PM
Steve Case writes:
[[Harold Pierce #33 is right. The six or seven billion people in the world burn stuff every day of their lives. Do we really think we can regulate them all to change their way of life?]]
Yes. And, more importantly, switch to other sources of energy.
[[ If the production of CO2 is going to change the climate, then we ought to prepare for it. It makes more sense to get off the tracks then it does trying to stop the train.]]
Not if the train is five miles away and you have the engineer’s cell phone number.
5 février 2008 at 4:24 PM
Re #39 [Steve Case] “If the production of CO2 is going to change the climate, then we ought to prepare for it. It makes more sense to get off the tracks then it does trying to stop the train.”
In this case, getting “off the tracks”, means getting off the Earth. How do you propose we go about it?
5 février 2008 at 4:34 PM
[I’ve been thinking the Earth (and therefore the supply of fossil fuels) was finite!]
Well, there is some dispute about that. Fossil fuels may not be the correct term for oil as we know it and it may not be finite.
http://planetgore.nationalreview.com/post/?q=OTY0NzIzMzQ0YTA1NWJkOWQ1ZmYwNzE2NTU1YjQ2Mjg=
[Response: This is a typical over-reaction. It is well known that not all hydrocarbons are biogenic (methane on Mars and Titan anyone?). Showing that this can be seen on Earth is a long way from showing that all oil is produced that way (it’s not), let alone that it implies that supplies are effectively infinite. - gavin]
5 février 2008 at 4:45 PM
Re #43 Barton,
If you have got the engineer’s cell phone number could you please let me have it so I can ring him and get him to stop?
Of course if that is the number of the White House then I have to warn you that it does not seem to work. They tell me there is a speed fiend in the cab who will stop for no one
5 février 2008 at 4:48 PM
Is there such a thing as a point of diminishing returns in using meta ensembles-kind of a Tower of Babel effect?
Will we go from storage needs of 100s terabytes to quadrillion bytes and higher? This feels like it can lead to complex logistical problems.
5 février 2008 at 5:03 PM
B Buckner (#24) wrote:
Ocean surface temperatures go up and down at a smaller magnitude in sync in the short-run due to their greater thermal inertia. They are being warmed or cooled at the same time, but given a general, long-term warming trend will take longer to warm up to the point that the earth’s system achieves radiation balance — with their warming pushing the radiation balance a little further away due to increased water vapor pressure coming off their surfaces leading to a further enhancement of the greenhouse effect due to the water vapor content of the atmosphere.
But the thermal inertia is just part of the problem. There is also ocean circulation, primarily in terms of the thermohaline but also in terms of ocean waves, which redistributes the heat to deeper waters. In the case of thermohaline circulation, it takes an individual molecule take on the average 3500 years to make a complete circuit,. It will take a great deal of time for the ocean to achieve the eventual quasi-equilibrium heat distribution - which is why the last 20% that Gavin inlines about takes so long.
5 février 2008 at 5:22 PM
gavin,
I thought I would let you know that the ice coverage for the Arctic Ocean is back to normal. I knew you were concerned about it last month, but now we can all sleep soundly, knowing the polar bears will last a few more months, at least.
http://arctic.atmos.uiuc.edu/cryosphere/
[Response: Only if your definition of normal is 1 million km2 less than climatology. - gavin]
5 février 2008 at 5:33 PM
Re: #41
And if the “stuff” weren’t, then the oxygen to burn it is. Even ignoring for the sake of argument our own breathing needs.
(Reductio ad absurdum… the Earth will become uninhabitable in any one of a broad palette of ugly ways, long before even getting close to this limit.)
5 février 2008 at 6:48 PM
Re Steve Case @ 39 “If the production of CO2 is going to change the climate, then we ought to prepare for it. It makes more sense to get off the tracks then it does trying to stop the train.”
You “it’s inevitable and we can adapt” guys keep forgetting that a warmer climate is only one result of increased CO2. It will also result in a more acidic ocean and a greatly altered marine food chain, so “adapting” also means that part of the Human population that relies on seafood for its protein source will have to find something else or do without.
5 février 2008 at 8:47 PM
Gaelan, I will take the best guess of the climate scientists–since it is based on evidence–over, say, yours, which is not. The fact of the matter is that if you have a climate sensitivity much less than 3 degrees per doubling, there are a lot of paleoclimate and other results (e.g. effects of volcanos, the “cooling” of the mid 40s to mid 70s) become quite difficult to explain. Perhaps you are unfamiliar with the way a scientist “guesses”.
5 février 2008 at 8:50 PM
Regarding train analogies, I suggest that the old movie “Runaway Train” might be appropriately cautionary.
But, given this is about archiving, I applaud those who are doing it: it’s hard work, and is a (mostly) thankless task.
5 février 2008 at 8:55 PM
Trying not to be too off-topic, but I’ve been wondering this for awhile and this most recent effort by Gavin includes some potentially relevant material:
“that is, the weather pattern on Jan 31, 1967 in one realisation will be uncorrelated to the weather pattern on Jan 31, 1967 in another realisation, even though each run has the same climate forcing …. … there is certainly a degree of unforced variability even at decadal scales (and possibly longer).”
This makes sense to me. But relating it to a nagging question about initial conditions, etc, after we obtain enough observations subsequent to Jan 31, 1967, is it possible to infer the initial conditions? That is, is it possible to get enough historical data such that the unforced variability can be incorporated and all models of future climate change can have the same starting point?
Now you know why I haven’t asked this question before. Perhaps I’ll find a way to ask it intelligibly in the future.
5 février 2008 at 9:00 PM
Hi Nick, Overfitted is probably a better way to say it as “overfit” conjures a picture of a model on steroids.
The weighting procedure works for “statistical models” more than dynamical models, but you can infer parameters in dynamical models. Here’s an interesting reference:
http://www2.fmg.uva.nl/modelselection/presentations/AWMS2004-Burnham-paper.pdf
I’ve been looking at some of this stuff in assessing reliability of microelectronics in high-radiation environments of space.
5 février 2008 at 9:37 PM
Re: #49
Russell, the ice area has obviously increased during the winter, but it’s still 1 million square kilometers lower than the 1979-2000 average. And, more importantly, the new ice is much thinner than the old ice (the thick ice that had been there for many years), so that next summer the melting will be faster and deeper. We are nowhere back to normal, even if the area had gone back to the 1979-2000 average, and you shouldn’t feel so good about it. Even if we had an average area of very thin ice, that would still not be good enough, because this young ice would melt very quickly next summer. You can only feel good about the polar bears if we go back to 79-00 average coverages for many years in a row to guarantee that the thick, multi-year ice covers the same area it did before.
5 février 2008 at 10:06 PM
Someone else has discovered winter. It’s amazing how many people were unaware of it until this year. Even more amazing is how so many denialists seem convinced that CLIMATE SCIENTISTS are unaware of winter.
5 février 2008 at 10:12 PM
#49, It is not “normal” , one word demonstrates this: volume. Another is plainly visible to anyone with remote sensing knowledge, there are more leads amongst a vastly wider area of first year ice. “First year” ice is vulnerable to re-melting. Much more so than ice twice or thrice thicker. The big question is whether immediately under ice biological and inorganic gaseous feedback is unleashed right now with little effect in darkness, or whether there will be a massive release this spring when sunshine triggers photochemical cloud and fog coverage, reducing the impact of sunlight. The latter scenario will be the only saving grace from a greater melt.
High Arctic sunrise from the long night just happened, in very cold surface air, but aloft there is a thick layer of warm air, giving a weak refraction boost, from over the ice of Barrow straight. Its too early to say how strong and pervasive this warming is, but similar weak refraction starts were 2005 and 2007.
5 février 2008 at 11:50 PM
Gavin,
Thank you; Meehl, et al (Science 307, 1769) gives exactly the comparison of transient responses I was looking for.
Along similar lines, could somebody refer me to a good paper on the observed radiation imbalance? I’m seeing that it’s on the order of 1 W/m^2; this is relatively small. Can it be measured with confidence?
6 février 2008 at 5:07 AM
wayne, how does it look from your high vantage point? The recent satellite photos of ice breaking up in the Beaufort sea were quite unsettling.
6 février 2008 at 5:13 AM
Re #49
I thought that climate models predicted the loss of summer sea ice and not winter sea ice for many years to come. Any loss of winter sea ice would be worrying, after all it is dark for 3/6 months, ice is boudn to form in open water.
6 février 2008 at 8:04 AM
Re #57
Careful where you point that sarcasm! The recent improvement in the NH sea ice anomaly is not just typical winter re-growth, because the 1978-2000 baseline for the anomaly includes seasonal variation - it’s not just a constant value. That’s why, if you look at the “tale of the tape” plot, you don’t see the huge seasonal of ~ 10 million square kilometers.
(That said, the arguments about thin ice being at risk next summer seem quite plausible to me. I’ve noticed river basins can appear to have completely frozen over in a 24 hr span, but that ice can be lost a lot faster than cover that’s a result of many days or weeks of cold.)
6 février 2008 at 8:27 AM
RE#49
And an other comment on ice extend in winter. Of course the extend is back to ‘normal’. There is an other reason why the anomaly in winter extend is less then in summer. The extend is limited by land. Without Siberia and Canada maybe the extend would have been 19 mln km2 in the old days, and now 15 mln in a warmer climate. But due to the land mass these extends are cut off to less then 14. Have a look at the ‘regional graphs’ at cryosphere.
6 février 2008 at 8:55 AM
#61 Pete Best,
“I thought that climate models predicted the loss of summer sea ice and not winter sea ice for many years to come.”
You’re right, Micheal Winton of GFDL has done an interesting paper on the stability of a seasonal Arctic ice cap in models. From his homepage: http://www.gfdl.noaa.gov/~mw/ it’s the pdf under “New Publication” - Sea ice-albedo feedback and nonlinear Arctic climate change.
As an aside…
Cecilia Bitz has some conference slides here: http://dels.nas.edu/basc/CRC0507/CRC%20Presentations%2011-07/Bitz_NRC_Nov07_corr%5B1%5D.pdf
Bearing in mind I’m working from the pdf - I have not heard the lecture…
Bitz argues that next year’s minima will be around the established linear trend for 1979-2006 (page 12), in other words last year (2007) will not be the start of a new trend.
On page 11, she shows a negative correlation for a 1 year lag.
What’s being done here is that the data series for detrended September extent minima is correlated (checked for matches) against itself, with a lag applied. So where there’s no lag (lag=0) you get a correlation of 1 because you’re correlating the sequence with itself, but for a 1 year lag you get almost -0.2, i.e. no match.
This can be seen on page 9 where successive record minima (circled in blue) since 1979 have always had more than 1 year between them.
Dr Bitz concludes that:
1) “PDF of anomalies becomes wider as ice thins, so expect bigger anomalies in future.”
2) “Zero one-lag autocorrelation, so no reason to expect big anomaly in 2008 (in my opinion)”
Which seems reasonable given her argument.
However as I’m looking at perennial ice as a damping factor on ice albedo feedback, I find myself wondering if the perennial ice is now so reduced that such reference to past behaviour is no guide to the future. The QuikScat images seem to show a significant reduction in thick ice between this year and the previous 2. e.g. bottom of this page, 4 Jan 2006, 2007 & 2008. http://ice-glaces.ec.gc.ca/App/WsvPageDsp.cfm?id=11892&Lang=eng
If I had to bet, I’d go for a summer minima of below 5 million km^2, either way we’ll know by October 2008.
That said,
Cecilia Bitz is an accomplished physicist, expert in modelling in the polar environment.
I’m just a bloke with a degree in electronics…
6 février 2008 at 9:35 AM
“I thought that climate models predicted the loss of summer sea ice and not winter sea ice for many years to come. Any loss of winter sea ice would be worrying, after all it is dark for 3/6 months, ice is boudn to form in open water. …”
It’s called winter for a reason. I guess I’m not getting it, but pointing out how much ice reforms in the Arctic in the wintertime seems just plain silliness.
Want a man-sized bet, bet on whether perennial ice recovers or declines.
6 février 2008 at 9:58 AM
In the subject post, Gavin states:
“……… So any comparison of climate models and data needs to estimate the amount of change that is due to the weather and the amount related to the forcing. In the real world, that is difficult because there is certainly a degree of unforced variability even at decadal scales (and possibly longer).”
Should the daily, seasonal, or annual weather be divorced from the forcing in this way? After all the the daily, monthly and annual averages and extremes of weather data, like temperature, precipitation, ice and snow accrual or lessening, taken over many tens of thousands of days are what climate is composed of.
Many of the weather events we’ve been experiencing, especially in the last few decades likely been so intertwined with forcing, that it appears that it’s not only difficult to separate natual variability from forcing but something beyond our present grasp.
6 février 2008 at 11:03 AM
re: #57 & #58
My understanding of an average means that some examples will be less and some more. If an element is less than average, yet still well within the bounds of “normal”, it is not a cause for concern.
My point to gavin was that we have a poor understanding of what constitutes an “abnormal situation” and what constitutes “less than average, yet still within historical norms”. If we had 5000 years of arctic sea ice records, it would be pretty obvious. We have about 40 years, with no records pre-AGW.
A reduction in the average over time, is more where the truth lies, but that will require some patience. Something in very short supply.
6 février 2008 at 11:53 AM
Re: Sea Ice
In fact we do have data on sea ice prior to the satellite era; it support the hypothesis that it’s been in serious decline in the northern hemisphere, and in decline in the southern hemisphere as well. I posted on the topic here.
6 février 2008 at 12:26 PM
Sorry Gavin,
Multitasking day at the office. Could you expand on your reply to the doubting Thomas? Thanks.
Re: Only if your definition of normal is 1 million km2 less than climatology.
I’m thinking of coining a few more bon mots to Chris Booker.
http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2008/02/03/nbook103.xml&posted=true&_requestid=365933
Best regards
Mike
6 février 2008 at 12:47 PM
Tharanga–
I think the information on radiative forcings you want is here: http://data.giss.nasa.gov/modelforce/
I used those, modified to included monthly data on stratospheric aerosols after volcanic eruptions, to fit to a simple energy zero dimensional, transient energy balance model to data. I get plots like the one shown here.
It’s not entirely clear what my fits mean since the zero-dimensional model is a huge simplification. (It’s the same model Schwartz 2007 used in his paper.)
Still, assuming something can be learned from this fit, (and I don’t find any blunders) my current results suggest the climate time constant for the climate based on temperature measurements at the planet’s surface, is about 8-10 years. (No errors analysis done, yet. I’m also doing some consistency checks.)
If correct, this would suggest that if we stopped adding CO2 or other GHG’s to the planet now, and there were no major volcanic eruptions or other dramatic events, the surface would reach 80% of the equilibrium value in roughly 16 years. (I can’t remember off hand how high it climbs; it’s enough we’d notice. )
6 février 2008 at 2:24 PM
#67 Your understanding is flat wrong, what is there not to comprehend? Less ice volume, means more open water in the summer. What is normal was dictated well beyond modern surveying days, the Bowhead whales of the Atlantic and Pacific are genetically distinct, meaning that the ice barrier between the North Atlantic and Pacific spans multiple thousands of years. Shorter time span, brings us back to the 16th century, when first known attempts to find the North East and North West passage were done, none successful till a very smart Norwegian, Amudsen on the Fram slowly found the Northwest passage in the early 1900’s, after 2 years froth with danger and boredom. Now a days the same path can be done in a couple of weeks.
6 février 2008 at 3:33 PM
#69 Mike Donald,
If you’ll forgive me for butting in to take the load off someone busier than I…
1) From Cryosphere Today: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.jpg
Looking at that graph shows a preponderance around 14million Km^2 with a sag in winter maximum to around 13million Km^2 since 2003. i.e. 1million km^2 below the previously typical extent.
2) Seasonal trends are here: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seasonal.extent.1900-2007.jpg
Chris Booker….
After the day I’ve had at work I needed a good giggle, thanks for that link Mike.
Cryosphere Today Homepage: http://arctic.atmos.uiuc.edu/cryosphere/ source of the other links in this post.
6 février 2008 at 4:27 PM
In 62 David writes “(That said, the arguments about thin ice being at risk next summer seem quite plausible to me. I’ve noticed river basins can appear to have completely frozen over in a 24 hr span, but that ice can be lost a lot faster than cover that’s a result of many days or weeks of cold.)” This has nothing to do with climate change, but may be of interest. If I have interpreted what David means, let me offer an explanation. When fresh water ice freezes, the ice crystals are vertical. When the ice thaws, some of these vertical crystals tend to stay intact. If you examine fresh water lake ice just before break up, the ice can be up to a foot thick, and at a distance appears to be solid. However, on close examination the ice is “rotten”; a whole series of vertical crystals with nothing much holding them together. In Canada, the lake where I have my cottage typically is completely ice covered one day. Then for some reason a small break in the ice occurs. The wind unsettles the water, and in a matter of a few hours, the entire lake is ice free, with a few chips of ice around the shore. The very rapid break up of fresh water ice in the spring is a very well known phenomenon. HTH.
6 février 2008 at 4:27 PM
Re 56. Is there any reference for the assertion that “new ice” melts faster than old? One could also think that, as old ice is dirtier and more porous than new, it would melt faster. (As we know, the old ice is on top, so it is first exposed to the sun.)
It is also possible that the age of the ice is not as important as the density of the ice, which is largely determined by the speed of freezing and wind conditions during freezing. But of course, the decisive factor is total thickness: the thicker the cover, the better it withstands summer.
But I may be quite wrong. Could somebody from the RC group could tell us something about how the models handle these variables?
6 février 2008 at 5:27 PM
Re #41 There are about 15 trilion barrels of oil equivent in heavy and extra heavy crude oils, oil shale, and tar sands. Coal can be readly converted to liquid hydrocarbons. South Africa gets about 40% of its liquid hydrocarbons from coal. Google SASOL.
World supply of oxygen: Over every square foot there is a column of oxygen that weighs about 440 lbs. There is additional oxygen dissolved in water. We will never ever run out of oxygen, which by the way is a renewable resource.
To all skeptics and deniers of fossil fuel facts and reality, I stand by my post (#33).
6 février 2008 at 5:51 PM
Re Gavin’s comment in 23
I consider SLR from thermal expansion to be De minimis. We can engineer our way around a meter/century SLR. It would not be cheap or pretty, but it is doable.
The real questions are about sea level rise from permafrost melt and ice sheet dynamics. How fast and how soon could these occur?
A seasonally ice free Arctic Ocean can be expected to provide more latent heat for rain in permafrost areas which could accelerate permafrost melt. Moreover, other Arctic surface water could drain to the ocean through pseudo karst formed by melting permafrost. In a warming Arctic, this could be a rapid process. And, as late as last November, broad swaths of Greenland received rain. That astonished (and worried me) much more than the sea ice melt last summer. I have done a bit of ice climbing, and our rule of thumb was always, “Ice that gets rained on, falls apart.”
I am starting to see Arctic storms that sit on boundaries between (warm) open water and ice, I conclude that these storms are driven by the temperature differential between that water and the ice. This provides an effective (but local) mechanism for the transfer of heat from the ocean to the ice. It is good physics, but I do not see it in the GCM. Then, that heat can be rapidly advected into the ice. Given the complex phase transitions of ice under high pressure as it approaches 273K, there is the potential for rapid, progressive, structural failure of big ice by mechanisms not contemplated in the GCM.
In terms of percentage of volume, how much of the Arctic sea ice has melted in the last decade? Show me a calculation that demonstrates that a combination of unusual weather and changing ocean currents (as in the recent Arctic) could not produce similar percentage of volume change in WAIS in the next decade. Only a fraction of a degree of warming would be required to move from “stabile” to melting. A hint of the current situation is at (http://www.osdpd.noaa.gov/PSB/EPS/SST/data/anomnight.2.4.2008.gif, which shows water in the area warmer than it was in 1979-2000. Such a change in WAIS volume would change sea level.
I worry when I see models (i.e. University of Maine) that suggest that much of the base of WAIS is at 0C. I know that under pressure, ice melts at less than 0 C. What is required to raise the temperature of some fault plane in the ice some fraction of a degree and have a chunk of ice crumble, and flow into the sea? At some point, as the ice warms, the potential energy of the ice itself will provide the activation energy. It will be sudden. Will it be a surprise?
( http://nsidc.org/iceshelves/larsenb2002/animation.html )
Gavin, would you swear by your FORTRAN manual that these issues have been investigated, and a progressive collapse of any ice sheet could not occur in the next 30 years? Would you like to show me a good model of “pseudo karst formation in permafrost structures” in your Archive? Would you say that NOW, we have a much better understanding of ice sheet dynamics than we had of Arctic Sea Ice melting in the fall of 2004? All known factors considered, I do not think we have a good estimate of how fast sea level change is likely to occur. The fact that the literature on the topic is De minimis does not give me confidence. I would love for you to remind me what an ignorant amateur I am by pointing me to the literature. Come on Hank, tell me my Google is brain dead, and that there is in fact, a big pile of recent literature on dynamic ice sheet modeling that I am just not finding. Please tell me that I am miss-reading ( http://ralph.swan.ac.uk/glaciology/adrian/luckman_GRL_feb06.pdf )
“The period of continued warming and thinning appears to have primed these glaciers for a step-change in dynamics not included in current models. We should expect further Greenland outlet glaciers to follow suit.”
(And, that does not even allow for the kind of serious rain that Greenland has seen in the last couple of years. My Google still finds a few weather reports.)
In short, unless the summer rains in Greenland cease promptly, and the Arctic Ocean returns to its old levels of sea ice, and the waters around Antarctica cool rapidly, we must consider the possibility of rapid (more than 10 cm/decade) sea level rise in the near future (30 years.) Frankly, I expect very rapid SLR, and sooner rather than latter. Absence of prediction in the literature does not mean it cannot happen.
6 février 2008 at 6:28 PM
Aaron, the modelers say, quite credibly, that they can’t model this area without actual physical observations, and the International Polar Year scientists are out there on the ice and oceans right now, frantically busy collecting observations.
The old assumption that nothing was going to change is clearly wrong, but I doubt that lets the modelers change anything in particular in a useful way.
I’d love to be surprised, I’m sure work’s going on that amateur readers like me don’t know about. I’m sure Dr. De Quere et al, and others working on the ecology/biology/climate models, have a lot of input that depends on sea ice seasonal changes, for example
6 février 2008 at 6:30 PM
http://www.sciam.com/article.cfm?id=the-unquiet-ice
6 février 2008 at 8:18 PM
Harold Pierce,
No one denies the usefulness of fossil fuels. In fact, one could quite easily argue that they are too valuable to burn. However, I take issue with your contention that things must always be the way they are now. Brazil has come a long way with biofuels, for instance. In the ’50s one would have argued that farming in the desert was fantasy, but Israel and other countries have made the desert bloom with desalinized water.
If ever increasing fossil fuel consumption equates to the end of civilization, one would expect rational people to work toward alternatives. That we may fail in that effort is not indicitave of the impossibility of that task, but rather of the lack of rationality in our species.
7 février 2008 at 12:39 AM
“GISS received no additional money over our standard model development grants to do simulations for AR4, and most groups were in the same boat.”
I’m interested in some further clarification of this concept of “unfunded” work on simulations for AR4.
Perhaps this question is totally naive, but what is US funding of GCM development for, if not for contribution to IPCC assessment reports? Don’t US science agencies who fund this activity fully expect these models to be used for AR4? And if they do not, why should they tolerate the IPCC dictating how their expensive computing facilities will be used?
Thanks
Ryan
[Response: Funding is for general research into climate forcings, responses, processes etc. The US groups were not mandated to do simulations in support of AR4, but decided to do so because they felt that would further the research. I think that was definitely the right decision. If AR4 hadn’t come along, we would have probably done similar kinds of things, so adapting to their specifications wasn’t completely orthogonal to our research goals. - gavin]
7 février 2008 at 3:03 AM
Very interesting article..scientists by nature are a very pedantic lot.that’s their strength but also their weakness as well. By the time we get enough data that statistically show to all and sundry that the level of forcing as apposed to natural variablty is beyond doubt the party’s over, the spilt beer and broken champagne glasses has been cleaned from the floor the last of the partier’s has dozed off in the corner and the cockroaches are out to play. It’s the same ol’ boiling frog scenario over and over again. It’s up to the climate scientists to take an avanced course in assertiveness and scare the pants off their respective ministers and senators into immediate action. Also to keep the pressure on the world media to keep reporting climate change stories. What do you guys think?
7 février 2008 at 5:52 AM
re #79
Its not the end of civilization that matters Ray but the warming of the globe that seems to be the issue. In fact it is not doubted anymore that the end of cheap oil is upon us (its peak) and that we must seek out the more expensive heavy oils now in order to meet world demand.
By heavy oil I mean the Athabasca oil sands of Alberta, a collossal resource of upto 2.5 trillion barrels of which current some 200 billion barrels is known to be recoverable, after that it needs new technology and its get more expensive to deliver it. The same goes for the potential 1.2 trillion barrels of heavy oils in Veneuzla and there are some more in Brazil and the USA. If these resources come online then expect much more warming of the planet beyond 2C.
Projected oil consumption of 115 million barrels per day is required by 2030 (2% annual increase) and the likelihood of this being met by conventional oil resources of not good as it peak is here. Therefore only unconventional heavy oils can potentially meet this demand. Biofuels possibly can help out but not the way they do it in Brazil from growing sugar cane, it will not scale to global proportions. Switch grass and algae methods of the current second generation leaders but they will not come online any time soon in any great quantities to stop the oil companies from attempting to dig up Alaska, Iraq, persuading OPEC to pump more etc.
7 février 2008 at 6:01 AM
#72 CobblyWorlds
Ta for those excellent links. I especially like the side by side comparison of present and previous ice coverage. Anyrate the key parameter should be ice mass - not areal extent. I reckon a remake of Ice Station Zebra will very very boring. [smiley face]
7 février 2008 at 6:20 AM
Re #75, 15 trillion, that is just a fugure you have pulled out of the air regarding oil sands and heavy oils. Its 5 trillion at most, 2.5 in Athabasca, 1.2 trillion in Venuezla (orinoco belt) and 1.5 else where in the world unless you know some more massive deposits unknown at the present time.
7 février 2008 at 8:09 AM
Re ice stability: a quick and dirty calculation* seems to indicate that thinner, one year ice will allow a larger phyto plankton population beneath it. Breaks in the thinner ice will allow DMS produced by that higher population to leak out and form more fogs and low level cloud, increasing albedo and preventing excessive melting. Very Gaia.
I hope someone is checking DMS levels.
JF
*= guess
7 février 2008 at 11:16 AM
Lawrence,
You wrote - “It’s up to the climate scientists to take an advanced course in assertiveness and scare the pants off their respective ministers and senators into immediate action. Also to keep the pressure on the world media to keep reporting climate change stories. What do you guys think?”
I certainly agree that the climate scientists should take an advanced course in assertiveness, but trying to scare the politicians has been tried and failed. The politicians only answer to their electors. It is the public that has to be convinced. When the voters speak then the politicians will jump.
The IPCC has been producing reports for nearly 20 years now but what effect have they had? In 1990 when the first IPCC report was issued oil consumption was 66.6 million barrels per day. It is estimated that in 2010 it will be 91.6. Yet the AR4 is still begins with a “Summary for Policymakers.” The scientists just don’t seem to realise that it is not the politicians but the public who decide how much oil they is burnt, even if they are not conscious of it. The politicians cannot stop their constituents flying off on vacation nor jet skiing when they get there, and still get re-elected.
As long ago as 1989 Stephen Schneider wrote:
“On the one hand, as scientists we are ethically bound to the scientific method, in effect promising to tell the truth, the whole truth, and nothing but — which means that we must include all the doubts, the caveats, the ifs, ands, and buts. On the other hand, we are not just scientists but human beings as well. And like most people we’d like to see the world a better place, which in this context translates into our working to reduce the risk of potentially disastrous climatic change. To do that we need to get some broadbased support, to capture the public’s imagination. That, of course, entails getting loads of media coverage. So we have to offer up scary scenarios, make simplified, dramatic statements, and make little mention of any doubts we might have. This ‘double ethical bind’ we frequently find ourselves in cannot be solved by any formula. Each of us has to decide what the right balance is between being effective and being honest. I hope that means being both.” (Quoted in Discover, pp. 45–48, Oct. 1989; for the original, together with Schneider’s commentary on it misrepresentation see also American Physical Society, APS News August/September 1996. [my emphasis]
http://en.wikipedia.org/wiki/Stephen_Schneider
In the most recent IPCC AR4 the true extent of the sea level rise has been suppressed. The rise due to melting ice has been omitted, with a note saying this was because of uncertainty of how much it would be. What they should have done is published the largest estimate, with a note saying this might be an over-estimate since the amount of melted ice was uncertain. That is being perfectly truthful, not being misleading as the AR4 version is.
But it won’t happen. The scientists won’t admit that their strategy is incorrect. Then they would have to admit that they were wrong, and no-one will do that because it means losing face.
They will continue to play safe, but endanger the world!
Don’t you agree Gavin?
7 février 2008 at 11:33 AM
I very much appreciate the summary of the collected models and the discussion that follows. Two issues ocurred to me:
1. Nowhere was the actual size of data sets specified, except for ‘very large’ and ‘Terrabytes’. I’d like to know the size of an individual data set, group of same model sets, and whole ensemble of open access sets.
2. The reason for question one is that a number of people, myself included, have > 1T local storage and non-trivial amounts of compute capacity, and are already involved in climateprediction.net, about 50,000 active hosts currently. What is the possibility that this cross-model analysis could be written to run under BOINC control and distributed to many individual systems for a substantial increase in run capacity?
3. Have you considered asking Amazon or Google to host the open part of the datasets for no charge to assist in this process?
Three issues ocurred to me, that’s three issues. :-}
Note: For those interested, I created the PacificNorthwest CPDN team in 2004 as part of my ’spreading the word’ effort. Currently with 79 members, the team is #15 worldwide. I have given climate presentations at a number of SF conferences and am in the process of updating my out of date web site to include more info.
7 février 2008 at 11:51 AM
Re 85. It looks like we are all just guessing how thick “the ice” might be. (There was no answer from the RC crew to my earlier Q74.) But it is not certain at all that “new ice” is “thinner” than old. It all depends on the severity of the winter.
Take this Arctic winter as an example: the starting point was very little ice, but freezing in early winter was quite rapid, so one could assume that average thickness by March, when melting starts, is not exceptional, although the ice is “new”.
Sorry about all those quotation marks - I have no idea what they are supposed to convey. But let’s return to the topic next September.
[Response: New ice is always thinner than multi-year ice. You can get ~1 meter or so of sea ice growth in a season, which then ridges and compresses to give multi-meter ice by the end of the winter. Multi-year ice is generally thicker - up to 4m - higher in some pressure ridges, but it takes time to build that up. Most of the ice area that melts in summer is thin first year ice. - gavin]
7 février 2008 at 11:56 AM
A very interesting discussions and links, thank you.
Anyone in the know, please:
Does the “Northern Hemisphere sea ice” statistic include areas outside of the Arctic Sea proper and the Northern Atlantic? Such as the Bering sea, coastal seas off the Asian eastern shores and the Baltic sea.
Northern Atlantic has been warm this winter, and a constant southwesterly flow has kept the Northern Europe readings some 5 degrees warmer than usual, all winter long. In fact, one of the recent features is the complete absence of colder spells over here. The Baltic remains ice free, which is quite unusual. There is very little ground frost, so I presume our bacterial flora has been busy manufacturing more CO2 all winter long.
My sporadic checks on a few Siberian sites were mostly warm as well, except Verkhoiansk which has shown the usual -50 - -60 degC range. More to the west, Norilsk for instance did not live up to its reputation (only -25 - -30 degC).
Arctic seems primed for another large summer melt if the seasonal weather patterns are nearly the same as last year. Most important is the observation that winds have continued to push multi-year ice out to the Atlantic, which means still more first-year ice cover. In addition to being thinner, I believe first-year ice is rather brittle as it includes more occlusions of saturated brine than the slowly formed multi-year ice.
7 février 2008 at 1:25 PM
” … Most of the ice area that melts in summer is thin first year ice.” - gavin
No doubt that is true, but the way it reads sort of masks something.
When was the last accrual year for perennial ice? From whatever year scientists consider its modern zenith, what percentage of perennial ice has been lost?
7 février 2008 at 1:29 PM
Lawrence Coleman asks: “It’s up to the climate scientists to take an avanced course in assertiveness and scare the pants off their respective ministers and senators into immediate action. Also to keep the pressure on the world media to keep reporting climate change stories. What do you guys think?”
Under no circumstances should it ever be to “scare” anyone. While I am also frustrated with the inability of policy makers to at threats that extend beyond the expiration of their term in office, but the only weapon science has is the credibility of its practitioners. It is not inappropriate to do “how bad can it be” analyses, but our emphasis should be on preparing for credible threats rather than just getting people off their fat, complacent asses.
As Mark Twain said, “If you tell the truth, you’ll eventually be found out.”
7 février 2008 at 2:25 PM
A quick thought in reply to Robert Rohde’s comment about the limits on use — seems to me the Globalwarmingart pages are ideal material for a ‘research project intended for academic publication’ specifically on how information can be presented so as to be understood.
There are plenty of college first year students each year who have little exposure to scientific information.
Certainly enough to divide into groups and test comprehension of basic understanding of how the world works. Start with Piaget’s basics (grin).
Robert, I suggest circulating a memo to the psychology/sociology or even (gasp!) political science and economics departments.
Someone must be working on — or would like to work on — studying how information can be presented graphically so as to be understood.
To prepare that material you’d certainly be justified in drawing on the current database, and want to compare new information to prior to see if a graphic can be created that gets across what’s different.
The very simple questions would include
– left to right or right to left?
– changing scales (geologic time, then “last 200 years”) on a chart — do people see it?
Just saying. It’s the great question of the age, can people comprehend science. It’s got to be done with pictures. You’re it.
7 février 2008 at 2:46 PM
Ray,
You wrote ‘As Mark Twain said, “If you tell the truth, you’ll eventually be found out.”’
No doubt you will agree that the non-sceptic scientists are telling the truth, but when they are found out it is going to be too late!
7 février 2008 at 3:40 PM
Re # 64
Traditionally, Arctic sea ice was insulated from the warmer, saltier water below it by several meters of very cold, fresh water that floated on the surface of the salt water below. (see http://www.acia.uaf.edu/PDFs/ACIA_Science_Chapters_Final/ACIA_Ch09_Final.pdf)
As the multiyear ice melts, this insulating layer is subject to storm mixing, i.e.,the chaotic wave systems of polar cyclones driven by a temperature differential between open water and extant sea ice.
The open water absorbs heat, and cyclones transfer this heat to the sea ice as rain. Note; last summer there were periods when research activities on the Arctic sea ice were suspended because of rain. Rain in the high Arctic? That was a 6 sigma event. It changes the rules of the game. That should have made headlines everywhere. It did not. The researchers were so busy with their “science” that they did not make a big deal of the really interesting event going on all around them. (After ice is rained on, it absorbs more sunlight and melts faster.)
Loss of the freshwater insulating layer from the surface of the Arctic Ocean means that the maximum refreeze temperature for new sea ice is (-1.8C) rather than the (0C) when the surface fresh water is retained. Thus, it must get colder to freeze new sea ice. It also means that the first year ice is saltier and has a lower melting point. Thus, first year ice frozen from saltier water will melt much faster than first year ice frozen from less salty water.
Since 1998 (at least), warm, salty water has been flowing into the Arctic basin from the North Atlantic, and more recently from the North Pacific. This additional heat facilitates Arctic sea ice melt. This additional salt facilitates sea ice melt. According to the Navy guys in Monterey, some of the multiyear Arctic Sea ice has been melting twice as fast from the bottom up as from the top down.
Measures of ice area do not reflect ice volume that have melted. Much of the extant “multiyear” ice is thinner that it ever was before, and if it gets a bit of rain water on it, it will melt fast. If chaotic wave systems “pump” the fresh water out from under this ice, so that it is floating in warm salt water, it will melt fast. Moreover, from overhead, ice floating in salt water will appear thicker than ice floating in fresh water. We may not have a good measure of the volume of the remaining ice.
Last, but not least, we have accumulating soot on the sea ice reducing its albedo.
Once we lose a significant amount of our Arctic sea ice, the system will tend to toward the loss of all summer sea ice in a highly non-linear fashion. Many of the effects listed above are not in the standard sea ice models, ocean current models, or atmospheric circulation modes. (At least I do not see them in there, but then, I do not work with these models and do not know their details.) They are small scale, local effects that occur on boundaries, and they never made it into the GCM. (Again, I do not spend my days with these models.) However, I think that cumulatively, they have a significant effect. With less sea ice and without its insulating freshwater, the Arctic sea is a new system, and statistical trends based on the old system are not likely to be valid.
A new day dawns in the Arctic, and a lot of ice is about to melt. Unless there are ice flows from the Greenland Ice Sheet, 2×10^6 km^2 is my estimate for 2008 Arctic Sea Ice minimum with general loss of Arctic (summer) sea ice by the end of the 2010 melt season.
7 février 2008 at 3:56 PM
Ref 89 Pekka writes “Does the “Northern Hemisphere sea ice” statistic include areas outside of the Arctic Sea proper and the Northern Atlantic? Such as the Bering sea, coastal seas off the Asian eastern shores and the Baltic sea.” So far as I am aware, ALL sea ice in the northern hemisphere is included. But, for example, I dont think it includes ice on the Great Lakes in the USA and Canada. As to what will happen next September, we are all very much “staying tuned”.
7 février 2008 at 5:35 PM
” As to what will happen next September, we are all very much “staying tuned”. …” - Jim Cripwell
Tell me why I’m wrong in believing the reality of what will happen in September is going to be either a new record, significant, or a nonevent, insignificant?
7 février 2008 at 9:45 PM
#85 Julian, Old ice is like a house, many micro and larger beings live in or just by it, I am not sure if new ice is more fertile than old, it may be a combination of both which is ideal. The coming fog extent will tell.
#94 Thanks Aaron, really good summary of some of the complexities involved,
winds play an important role as well. Remains also the question as to whether multi-year ice can rebuild to former expanses, especially when top old ice itself is a source of fresh insulating water, and also makes excellent tea….
8 février 2008 at 12:14 AM
Aaron Lewis comment #76 6 February 2008 5:51 PM wrote:
“I see models (i.e. University of Maine) that suggest that much of the base of WAIS is at 0C.”
please may i have a link, or a citation for these studies ?
8 février 2008 at 6:53 AM
#89 & #95
Indeed the sea ice situation here by the Baltic Sea is unusual this winter. I have lived my whole life on the south coast of Finland, and I can’t remember a year with this little ice. The situation varies from year to year, but what I find remarkable is that even Gulf of Riga, Gulf of Finland and most parts of Gulf of Bothnia are still open. Winter lasts another month or so, but according to the weather forecast no further freezing is expected in the coming days, it remains to be seen if there will be any at all.
Finnish Institute of Maritime Research updates ice situation on their website http://www.fimr.fi/en/palvelut/jaapalvelu/jaatilanne.html
There’s also interesting comparison to average (or “normal” as they call it) winter.
8 février 2008 at 7:12 AM
In 96 JCH writes “Tell me why I’m wrong in believing the reality of what will happen in September is going to be either a new record, significant, or a nonevent, insignificant?” You are absoultely right that in the great scheme of things, the amount of ice in the Arctic this September is a completely non-event. However, it is important because the proponents of AGW have said it is important; something about a “tipping point”. I am afraid I dont understand tipping points.
8 février 2008 at 7:44 AM
If this coming Septempber doesn’t set another record this year it most likely will in 2009. Having a run of consecutive record melts is very rare so I think we are due for an adjustment year where the melt mightn’t be quite as severe as the past few years, but the unmistakable trend is taking on an increasingly exponential appearence. Loss of sea ice begets further loss as the sun warms the growing expanse of ‘dark’ sea. Multi year ice is also heavily fractured in compostion with each season’s layering differing from the last..so it is anything but a homogenous mass but rather- rarefied crystalline with heaps of surface area exposed to the warming rays of spring and summer. Am am not a scientist but have a great interest in all things of a scientific bent and by what I can picture is that the artic territory will collapse like a pack of cards..very soon. Thanks Alastair and Ray for giving me further insight. So public education is the best way change governmental views? The media watching public I’ve found also tends to become increasingly cynical and war weary about climate change stuff especially in Australia..the echos of Ho-Hum are getting louder. What does the media do in that regard? Maybe to really include everyone in the street in this fight..which is absolutely true. Make everyone feel important for doing their contributing bit..maybe competitions as to which suburb changes over the most lights to CFL’s etc..ideas like that?
8 février 2008 at 10:11 AM
re 98
start at http://www.climatechange.umaine.edu/Research/Contrib/html/15.html
8 février 2008 at 10:15 AM
re 101
see http://www.uctv.tv/search-details.asp?showID=13459
The American Denial of Global Warming
(#13459; 58 minutes; 12/12/2007)
Polls show that between one-third and one-half of Americans still believe that there is “no solid” evidence of global warming, or that if warming is happening it can be attributed to natural variability. Others believe that scientists are still debating the point. Join scientist and renowned historian Naomi Oreskes as she describes her investigation into the reasons for such widespread mistrust and misunderstanding of scientific consensus and probes the history of organized campaigns designed to create public doubt and confusion about science.
8 février 2008 at 11:44 AM
Jim Cripwell, let me introduce you to the concept of the future tense. In English, the use of the word “will” prior to the clause that contains the verb generally conveys a sense that the events referred to take place in the future. For example, JCH says, “Tell me why I’m wrong in believing the reality of what will happen in September is going to be either a new record, significant, or a nonevent, insignificant?” The “will happen” would imply he is talking about next September, not last September. Since last September represented a record